SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4745aece3de6f2b8cdc21b9a9a98ad589481b5683c673a4db85fb614f03e9ec8' 
  AND token = 'r0ExgtJ/lYNbZu3nhMRydefxYaqV7FihGlvWR1j8GWQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}